The present disclosure is related generally to sutureless prosthetic devices such as for native heart valve replacements, and more particularly, to devices, systems and methods for treatment of valvular diseases such as aortic stenosis using a sutureless prosthetic heart valve.
Aortic stenosis is a condition where the aortic valve becomes more narrow and does not open fully, leading to increased pressure within the left ventricle, as well as decreased blood flow from the heart. Such a condition may lead to shortness of breath, due to blood backing up in the lungs, as well as light-headedness and fainting, due to insufficient blood flow from the heart to the brain and the rest of the body. Aortic stenosis is one of the most common valvular diseases, affecting 2-4% of adults over the age of 65 in the United States.
Aortic stenosis is typically treated by replacement of the aortic valve via open heart surgery. During open heart surgery, the patient is placed on cardiopulmonary bypass to maintain blood flow through the body while the surgery on the heart is performed. It is commonly understood that many risks associated with open heart surgery are directly related to the time the patient spends on bypass, and thus, the longer the time spent on bypass, the greater the risk of complications during the surgery. Moreover, due to this correlation, many patients are believed to be left untreated.
A recent trend, as an alternative to open heart surgery, aims to implant a replacement valve through a catheter, thereby eliminating the need for any bypass. Prosthetic heart valves that are collapsible to a relatively small circumferential size can be delivered into a patient less invasively than valves that are not collapsible. For example, a collapsible valve may be delivered into a patient via a tube-like delivery apparatus such as a catheter, a trocar, a laparoscopic instrument, or the like. This collapsibility can avoid the need for a more invasive procedure such as full open-chest, open-heart surgery.
Collapsible prosthetic heart valves typically take the form of a valve structure mounted on a stent. One type of stent on which the valve structures are ordinarily mounted is a self-expanding stent. To place such a valve into a delivery apparatus and ultimately into a patient, the valve must first be collapsed or crimped to reduce its circumferential size.
When a collapsed prosthetic valve has reached the desired implant site in the patient (e.g., at or near the annulus of the patient's heart valve that is to be replaced by the prosthetic valve), the prosthetic valve can be deployed or released from the delivery apparatus and re-expanded to full operating size. The self-expanding stent automatically begins to expand as the sheath covering the valve is withdrawn. Once the self-expanding valve has been fully deployed, it expands to a diameter larger than that of the sheath that previously contained the valve in the collapsed condition.
While collapsible prosthetic heart valves avoid the risks associated with open heart surgery, there remains unanswered issues regarding the longevity of the prosthetic heart valves compared to those implanted via open heart surgery. Further, it is commonly understood that the collapsible design feature of the valve limits the leaflet thickness and leaflet profile of the valve thereby limiting the maximum durability that can be achieved through a collapsible valve. There therefore is a need for improvements to the devices, systems and methods for sutureless prosthetic heart valves when treating valvular diseases which require cardiopulmonary bypass, by way of example, aortic stenosis.